This project consists of the continued implementation and evaluation of a developmentally based, long-term, comprehensive intervention designed to prevent conduct disorder and social maladaptation in adolescence and adulthood. The hypothesis will be tested that such an intervention will lead to proximal improvements in child behavior and family ecology and, in turn, that these changes will lead to the long-term prevention of conduct disorder. The project is being carried out at four sites (Durham, NC/Duke; Nashville, TN/Vanderbilt; rural Pennsylvania/Penn State, and Seattle, WA/U. of Washington). Two successive cohorts of children who will be followed over twelve years have already been identified, and a third cohort will have been identified prior to the start of the next grant period. Kindergarten-age children who are at high-risk for conduct disorder are randomly assigned to an intervention (child n=480) or control (child n=480) group. The intervention attempts to promote children's compliant behavior, social cognitive skills, peer relations, and academic success; to promote parents' and teachers' skills in child behavioral management; to assist teachers in promoting children's social competence; and to develop coordination between families and schools. This multi- system program is designed to provide intensive intervention for two year periods at two developmentally important transition points (school entry and the transition to middle school), and to provide less intensive criterion-based intervention, classroom-based tutoring and home visiting during the middle elementary school years. The effects of intervention will be evaluated in multiple theoretically based ways. In addition, representatively selected normative group of children in the control schools will be followed to provide normative comparisons for the intervention group, as well as to further investigate risk factors in the development of conduct disorder. Analyses of data comparing the first cohort of high-risk children and their families to the normative children and their families confirm the assumptions of the developmental model of conduct disorder on which this proposal is based. In the proposed three year grant period, intervention will focus on elementary school intervention and the developmental transition that occurs with entrance into middle school (for the first cohort). Further preventive intervention and evaluation is planned to complete the transition to middle school and early adolescence for all cohorts in a subsequent grant period.